This application relates generally to the monitoring of power consumed by electronic instruments and in particular relates to test apparatus for providing electrical connections through the fuse holder to permit measurement of the total current consumed by the instrument circuitry.
Electrical testing apparatus is known in the prior art. U.S. Pat. No. 1,984,493 to Pierce is typical. Pierce provides a compact tester having a power cord for connection to a power line. The power line cord of the apparatus to be investigated is then plugged into at least one receptacle on the tester. Circuits within the tester then allow monitoring of such parameters as voltage, current and power consumed by the apparatus under test. For many applications the approach disclosed by Pierce will be satisfactory. However, problems arise when attempting to use such a tester in monitoring some of the extensive and complex electronic equipment installations of today. Many installations comprise several relay racks of equipment interconnected by cables which may run in both overhead trays and under a false floor that also incorporates cooling and dust filter ducts. For these electronic systems the individual power line cords may not be readily accessible after the installation is complete. What is accessible though is the fuse holder which serves to protect each working assembly.
Almost every piece of equipment which consumes electrical power operates through a fuse which is generally accessible on either the back or front panel. The prior art discloses means for testing both fuse holders and cartridge fuses. The U.S. Pat. No. 4,281,888 to Seaman discloses test apparatus for continuity testing all the leads in a fuse block commonly used in the telephone industry. The U.S. Pat. No. 3,820,017 to Reichenbach discloses a continuity tester which allows a fuse to be checked in location. Neither of the above anticipate that the fuse holder is capable of providing contact points to which power monitoring apparatus can be temporarily attached.